Lumholtz’s Tree-kangaroo has a restricted distribution (extent of occurrence <20,000 km2 and area of occupancy < 2,000 km2). The number of locations is unknown but probably not substantially more than 10. The population size is >10,000 mature individuals. There is no reliable assessment of trends in population size, but limited information provides weak (and inconsistent) inference of continuing population decline. Declines over last, or next three generation period are unlikely to approach 30%, so are insufficient to qualify for criterion A.

This species is present in the rainforests between Ingham and Mossman in north-eastern Queensland, Australia. It is now largely restricted to upland rainforests because of extensive clearing of lowland rainforests. Its area of occupancy has declined substantially in upland areas because of clearing of prime habitat on basalt soils on the Atherton Tableland. About 41,000 ha of the original 66,000 ha of this habitat cleared (Kanowski et al. 2003). The elevational range is sea level to 1,600 m asl.

Kanowski et al. (2001a) estimated that the 650 km2 of high altitude rainforest (>800 m a.s.l.) in the Wet Tropics World Heritage area supported 10,000 to 20,000 individuals, and this would represent the majority of the population.

Winter et al. (2008) reported that its population size was stable. However, Laurance et al. (2008) reported a highly significant decline (of about 60%) in abundance in four intact rainforest sites sampled in 1986-87 and again in 2006-07, although this change may have been due to disturbance-related changes in forest structure and hence detectability (Laurance et al. 2008; R. Martin pers. comm. 2014). Kanowski et al. (2008) sampled nine intact forest sites in 1995-97 and again in 2006, six to eight months after Cyclone Larry had damaged vegetation at these sites, and reported a weakly significant trend for decrease in abundance across this sampling period, albeit with interpretation compromised by a small number of records for this species. However, abundance estimates based on spotlighting have some constraints due to low detectability (Newell 1999a; Martin 2005; R. Martin pers. comm. 2014) and population trends across the range of this species are not yet well established.

Lumholtz’s Tree-kangaroo is restricted mostly to rainforest habitats, but also extends along riparian vegetation through primarily open forest habitats, and less abundantly in wet sclerophyll forests along the western edge of the Atherton Tablelands (Kanowski et al. 2001a).

Lumholtz’s Tree-kangaroo is mainly nocturnal, but also intermittently active during daylight hours. Its diet mostly comprises foliage from a broad range of tree species and some vines, although Newell (1999a) noted that individual tree-kangaroos each used only a small set of plant species. It is predominantly arboreal.

Lumholtz’s Tree-kangaroos occupy some rainforest fragments (even fragments <20 ha) (Laurance 1990, 1991, 1995, 1997; Laurance et al. 2008), although populations in such fragments may have limited long-term viability. Individuals can disperse through unsuitable habitat, but at such times may be particularly susceptible to predation by dogs, and to being killed by vehicles (Kanowski and Tucker 2002).

Climate change and associated factors have been predicted to have a major detrimental impact on this species, acting directly or indirectly through reduction in rainforest area, reduction in foliar nitrogen concentration, habitat degradation due to increased incidence of severe cyclones, increased incidence of high temperatures, and reduced incidence of free water in mist (Kanowski 2001, 2004; Kanowski et al. 2001; Winter 2004). Williams et al. (2003) predicted that increasing temperatures will result in the significant reduction of the core environment for this species.

Lumholtz’s Tree-kangaroos are mostly solitary within loose social groups, typically with one male and several females. In high quality habitat (fertile recent basalt-derived soils), males occupy home ranges of about 2 ha, which may encompass the non-overlapping and smaller (1-2 ha) ranges of several females (Newell 1999a; Johnson and Newell 2008). Site fidelity is very strong, with individuals reported to stay in their home range even if clearing or disturbance renders it unsuitable (Newell 1999bc).

Breeding is broadly seasonal, with females producing a single young, mostly during the wet season. Age to maturity is two years for females and 4.6 years for males (Johnson and Newell 2008).

Historically, the main threat has been reduction of habitat, but this has ceased with the declaration of the Wet Tropics World Heritage Area, and the species appears to have been able to persist in the mosaic of fragmented habitat (particularly where there are available habitat corridors). On the Atherton Tableland, increased fragmentation makes them more vulnerable to predation by dogs, although strategic reforestation on the Atherton Tableland opens the possibility of some recovery of its original area of occupancy in the future (Maxwell et al. 1996). In agricultural areas where it occurs, predation by dogs and road kills represent threats. Climate change and associated factors have been predicted to have a major detrimental impact on this species, acting directly or indirectly through reduction in rainforest area, reduction in foliar nitrogen concentration, habitat degradation due to increased incidence of severe cyclones, increased incidence of high temperatures, and reduced incidence of free water in mist (Kanowski 2001, 2004; Kanowski et al. 2001; Winter 2004).

This species is present in the Wet Tropics World Heritage Area. The species has been promoted as a flagship species, and it has a very high profile in the region where it occurs. Recommended conservation actions for this species, from Maxwell et al. (1996), include: monitor distribution and abundance; study habitat utilization and population dynamics in fragmented and regenerating rainforest habitats.

Kanowski, J. 2004. What factors control the distribution and abundance of folivorous possums inhabiting rainforests of the Atherton Tablelands in north-east Queensland? In: R.L. Goldingay and S.M. Jackson (eds), The biology of Australian possums and gliders, pp. 539-548. Surrey Beatty and Sons, Sydney.

Kanowski, J. and Tucker, N. I. J. 2002. Trial of shelter poles to aid the dispersal of tree-kangaroos on the Atherton Tablelands, north Queensland. Ecological Management and Restoration 3: 137-138.